Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/10—Cores; Manufacture or installation of cores
  • B22C9/106—Vented or reinforced cores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/06—Permanent moulds for shaped castings
  • B22C9/067—Venting means for moulds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/22—Moulds for peculiarly-shaped castings
  • B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D21/00—Casting non-ferrous metals or metallic compounds so far as their metallurgical properties are of importance for the casting procedure; Selection of compositions therefor
  • B22D21/02—Casting exceedingly oxidisable non-ferrous metals, e.g. in inert atmosphere
  • B22D21/04—Casting aluminium or magnesium
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F1/00—Cylinders; Cylinder heads 
  • F02F1/24—Cylinder heads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F7/00—Casings, e.g. crankcases or frames
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F2200/00—Manufacturing
  • F02F2200/06—Casting

Definitions

• the present invention relates to the field of foundry and the casting of aluminum alloy casting parts.
• the invention more particularly relates to a casting core for casting aluminum alloy parts in a mold.
• the cores concerned in particular consist of a mixture of sand and binder.
• the foundry core is a part of the mold used to make a piece of metal and in particular aluminum alloy.
• the core is usually composed of a mixture of sand grains and binder.
• the foundry core allows the creation of interior recesses of a room. It is therefore wholly or partly immersed in the molten metal.
• This configuration is difficult to implement and its configuration requires permanent control, which is a disadvantage in itself.
• this type of system must suck sufficiently to avoid the problem of gas emissions but do not suck too hard to avoid the aspiration of metal in the core.
• the object of the invention is to overcome these limitations.
• the invention thus proposes a casting core for casting aluminum alloy parts in a mold, the core comprising a molding part, intended to be in contact with the molten metal, and at least one non-molding part, intended to to be located out of the molten metal, the core having at least one slot on the surface of the core and the slot extending from the molding portion to at least a non-molding portion to allow evacuation of the gases generated in the molding portion of the core during casting out of the molding portion.
• the invention thus proposes a simplified alternative to the techniques of the prior art by producing slots on the surface of cores. These slots create a space to evacuate the gases generated in the core, and at the same time the slots are thin enough to prevent the aluminum alloy from penetrating them. By drawing a preferential path for evacuating the gases towards the non-molding parts of the core, out of the molten metal (typically the spans), these slots make it possible to evacuate the gases that can be generated in the core, without implying the disadvantages mentioned above. -above.
• the invention also proposes the following features taken alone or in combination: the non-molding part or portions are spans adapted to hold the core in position inside the mold; the slots have a width adapted to prevent the molten aluminum alloy from penetrating into said slot; the slots on the surface have a width of less than 1 mm and preferably of 0.2 mm;
• the slots have a rectangular geometric profile, U or V; the slots have an average depth of between 0.2 and 2 mm, to allow the gas generated in the molding part of the core to circulate in the slots; the slots are made by laser;
• the slots are made by tooling with reliefs in the form of blades.
• the invention also proposes a mold adapted for casting castings, comprising a core as described above.
• the mold may further comprise a suction system adapted to suck in the slots generated gases, the suction being at the non-molding areas.
• the invention also provides a method of manufacturing a core as described above, characterized in that it comprises a step of etching said slots on the surface of the core using a laser.
• the invention also proposes a process for manufacturing an aluminum alloy part by casting molten metal by means of a previously described mold.
• the invention proposes a cylinder head for automobile obtained by a method of manufacturing a previously described part, as well as a motor block for automobile.
• Figure la shows a core according to the invention immersed in a molten aluminum alloy.
• Figure 1b shows a magnification of the core of Figure 1a.
• Figure 2a shows a sectional side elevation diagram of a mold and a core as defined in the invention, the molding portion is immersed in the molten metal.
• Figure 2b shows the core of Figure 2a seen from above, without the mold.
• Figure 3a shows a more accurate representation of a core according to the invention.
• Figure 3b shows a sectional view along the plane [ ⁇ '] of Figure 3a of the core as defined in the invention.
• Figure 4a illustrates different slit profiles (scales not necessarily respected).
• Figure 4b shows different types of slots with the burrs of molten metal penetrating inside these slots (scales not necessarily respected).
• Figure 5 shows a schematic diagram of a top view of the surface of the core immersed in the molten metal, within a mold, with possible circulation (arrows) in the gas slots generated in the core.
• Figure 6 shows the evolution of gas evolution as a function of the number of slots.
• FIGS. 1a, 1b, 2a, 2b, 3a, 3b a core 10 according to the invention is described.
• the core 10 is suitable for casting foundry pieces in a mold 20. These cast casting parts are made of aluminum alloy and are typically intended for the automotive industry. Typically, these castings are intended to be engine blocks or cylinder heads.
• the core 10 comprises a molding portion 11 which is intended to be in contact with the molten aluminum alloy 30.
• the core 10 also comprises a non-molding portion 12a, intended to be located outside the molten aluminum alloy 30.
• a core 10 comprises a plurality of non-molding portions 12a separated in particular by the molding portion 11.
• the core 10 is placed inside the mold 20 and is held there immobile thanks to the bearing surfaces 12b, which are generally non-molding parts 12a (see Figure 2a).
• the mold 20 comprises a sole 21, which constitutes the bottom of the mold 20, and at least one movable slide 22, which constitutes a side wall of the mold 20 when said slide 22 is closed.
• the sole 21 and the drawers 22 make it possible to produce the outer shapes of the castings.
• the drawers 22 are also adapted to immobilize the core 10.
• the bearing surfaces 12b are in this connection in contact with said drawers 22.
• the core 10 comprises at least one slot 13 located on the surface of the core 10.
• the slot 13 extends from the molding part 11 to at least one non-molding part 12a and thus makes it possible to create a preferential path for evacuation of the gases generated. to evacuate the gases generated in the molding part 11 out of said molding part 11 and, preferably, out of the non-molding parts 12a thereafter (see Figures 2a, 2b, 3a, 3b).
• the main function of the slot 13 located on the surface of the core 10, and which extends from the molding part 11 to at least one non-molding part 12a, is thus to create a preferential path for evacuation of the gases generated to evacuate the gases generated in the molding portion 11 out of said molding portion 11.
• These gases can thus be removed at a distance from the portion of the core 10 which will effectively mold the part to be manufactured. They can accumulate at the level of the non-molding parts 12, or be removed from these parts 12 if the slot 13 is brought into contact with the open air.
• Each slot 13 consists of a groove that connects the molding portion 11 to a non-molding portion 12a. In a preferred manner, given the structure of the cores 10, the molding part 11 of which is connected to two distinct non-molding parts 12a, the slot 13 connects the two non-molding parts 12a by passing through the molding part 11.
• the profile of the slots 13 is preferably rectangular, in U or in V. These forms offer a good compromise between the simplicity of manufacture and the efficiency that is, the capacity of the gases generated to circulate and be drained.
• the dimensions of the slits obey constraints related to the molten metal and the gases generated. This is to optimize the volume of the slot 13.
• the slots 13 thus have a width 13a such that the molten aluminum alloy 30 does not create on the surface of the piece apparent burrs 31 after cooling (see Figure 4b). For this, either the molten aluminum alloy 3 does not penetrate inside the slots 13 or it penetrates a given distance less than a quality criterion defined by a specification. Typically, the impact on the surface condition of the aluminum alloy must be zero or the value of the roughness of the casting must be unchanged with and without slots.
• width 13a to maximize the drainage of the gases generated and minimize the burrs 31. The optimization of this width 13a facilitates optimizing the volume of the slot 13, particularly in the case of fairly simple geometric profiles.
• the width 13a is a useful width, i.e.
• the width 13a is in particular a function of the types of aluminum alloy used.
• the width of the slots 13a is less than 1 mm and, preferably, less than or equal to 0.2 mm.
• FIG. 4b (given for illustrative purposes, without scale) illustrates various profiles of burrs 31 obtained for widths 13a different from slot 13.
• the slots 13 have an average depth 13b such that the generated gases can circulate inside the slots 13.
• the depth 13b of the slots 13 has theoretically no influence on the burrs 31 but the complexity, the cost and the fragility kernel, among others, increase with depth 13b.
• a value of depth 13b greater than 0.2 mm makes it possible in practice for the gases generated in the molding part 12a to circulate inside said slots 13. is greater than 0.2 mm and less than 2 mm.
• the path of the slots 13 is drawn so as to drain as much gas as possible by providing a preferential path for the flow of generated gases.
• the tracing plan is optimized to promote the circulation and drainage of the gases generated to minimize the pressure due to said gases.
• An advantageous tracing plan can thus for example consist in leaving the least areas of the molding part 11 without slots 13, ie ensuring that no point on the surface of the molding part 11 of the core 13 is at a distance greater than a given limit value, with respect to the nearest slot 13. In the case of several slots 13, the minimum and / or maximum spacing between the slots 13 can be determined.
• the slots 13 are preferably traced by maximizing the radii of curvature and limiting the angles, for greater reasons acute angles, to facilitate the circulation and drainage of the gases generated (Figure 3a).
• slots 13 do not intersect, in order to maximize the covered area for a given total length of slots 13.
• the non-molding parts 12a are advantageously litters 12b since the bearings 12b already act as non-molding parts 12a.
• the non-molding portions 12a which receive the slots 13 comprise means 40 adapted to allow the evacuation of the gases generated in the molding portion 11 ( Figure 2a).
• These means 40 can be made in different ways.
• the means 40 may consist simply of a fluid connection 41 between slots 13 of the non-molding parts 12a and a certain volume of air under pressure less than the pressure of the gases generated to be discharged (typically this pressure is the atmospheric pressure) said volume being typically much larger than the volume of gas generated.
• a bore or an opening 42 in the slide 22 allows said connection 41 between slots 13 of the non-molding parts 12a (here typically spans 12b) with the volume of air.
• the devices 40 further comprise a suction system 43 to promote the circulation and drainage of the gases generated in the slots 13 (FIG. 5)
• the slots 13 are preferably obtained by a laser 50. This technique is minimally invasive and allows a good accuracy in the realization despite forms of complex cores.
• This specialized tool may consist of an apparatus with reliefs in the form of blades (the slots 13 whose profile is V are typically obtained as well).
• the core 10 is installed in the mold 20 and fixed to the drawers 22 of the mold 20 by the bearing surfaces 12b.
• the molten aluminum alloy 30 is poured inside the mold 20 and surrounds the molding portion 11 of the core 10.
• the heat causes a gas generation inside the core 10.
• These gases then preferentially flow through the slots 13 and are drained to the non-molding parts 12a ( Figure 4), then to be evacuated by the exhaust means 40. There is thus no traces of gas emissions in the room. Choosing the width 13a slits in a suitable manner, it further avoids the burrs 31 on the cooled part.
• the use of the slots 13 on the core surface 10 makes it possible to reduce the pressure due to the gases generated inside the core 10 by allowing the generated gases to circulate and to be drained out of the molding part 11 via a cooling path. preferential circulation.
• FIG. 6 thus illustrates the results obtained.
• test pieces (including the reference test piece) have, apart from the possible slots 13, the same general geometry, and they consist of the same material.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Induction Machinery (AREA)

Priority Applications (7)

Applications Claiming Priority (2)

Publications (1)

Family

ID=50933311

Family Applications (1)

Country Status (9)

Cited By (1)

Families Citing this family (1)

Citations (3)

Family Cites Families (4)

• 2014
  • 2014-02-25 FR FR1451514A patent/FR3017811B1/fr not_active Expired - Fee Related
• 2015
  • 2015-02-23 EP EP15706774.5A patent/EP3110582A1/fr not_active Withdrawn
  • 2015-02-23 CN CN201580010307.2A patent/CN106170352B/zh not_active Expired - Fee Related
  • 2015-02-23 MX MX2016011031A patent/MX2016011031A/es unknown
  • 2015-02-23 US US15/121,359 patent/US20160361759A1/en not_active Abandoned
  • 2015-02-23 WO PCT/EP2015/053722 patent/WO2015128286A1/fr active Application Filing
  • 2015-02-23 JP JP2016553900A patent/JP2017506585A/ja not_active Withdrawn
  • 2015-02-23 KR KR1020167026428A patent/KR20160132872A/ko unknown
  • 2015-02-23 CA CA2940314A patent/CA2940314A1/fr not_active Abandoned

Patent Citations (3)

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